In a tablet having a board located just below a display, a temperature difference in a casing is large due to an influence of a heat generating component such as a CPU. It is desired to ensure a stable touch performance without a deterioration of an entire sensitivity even when the temperature difference in the casing is large. In an electrostatic capacity type touch panel, a capacity variation (an electrostatic capacity) receives an influence of temperature. Thus, when a heat source such as the CPU is provided in the vicinity of the touch panel such as the tablet, a temperature in a plane is uneven. The electrostatic capacity C is proportional to an area element and inversely proportional to a distance element by setting a dielectric constant as a coefficient. The dielectric constant increases or decreases to a rise of temperature depending on a material of the touch panel.
As a related art in comparison with the above-described touch panel, there is a touch panel using a control of a FUN or the like. However, since the FUN control serves to improve an environmental temperature, the FUN control does not directly apply an influence to the electrostatic capacity of the touch panel. Thus, an anticipated improvement cannot be supposed to be achieved depending on a working condition or an orientation of the FUN.